Merge branch 'rg/doc-workflow' into maint
[git] / builtin-describe.c
1 #include "cache.h"
2 #include "commit.h"
3 #include "tag.h"
4 #include "refs.h"
5 #include "builtin.h"
6 #include "exec_cmd.h"
7 #include "parse-options.h"
8
9 #define SEEN            (1u<<0)
10 #define MAX_TAGS        (FLAG_BITS - 1)
11
12 static const char * const describe_usage[] = {
13         "git describe [options] <committish>*",
14         NULL
15 };
16
17 static int debug;       /* Display lots of verbose info */
18 static int all; /* Any valid ref can be used */
19 static int tags;        /* Allow lightweight tags */
20 static int longformat;
21 static int abbrev = DEFAULT_ABBREV;
22 static int max_candidates = 10;
23 static int found_names;
24 static const char *pattern;
25 static int always;
26
27 struct commit_name {
28         struct tag *tag;
29         int prio; /* annotated tag = 2, tag = 1, head = 0 */
30         unsigned char sha1[20];
31         char path[FLEX_ARRAY]; /* more */
32 };
33 static const char *prio_names[] = {
34         "head", "lightweight", "annotated",
35 };
36
37 static void add_to_known_names(const char *path,
38                                struct commit *commit,
39                                int prio,
40                                const unsigned char *sha1)
41 {
42         struct commit_name *e = commit->util;
43         if (!e || e->prio < prio) {
44                 size_t len = strlen(path)+1;
45                 free(e);
46                 e = xmalloc(sizeof(struct commit_name) + len);
47                 e->tag = NULL;
48                 e->prio = prio;
49                 hashcpy(e->sha1, sha1);
50                 memcpy(e->path, path, len);
51                 commit->util = e;
52         }
53         found_names = 1;
54 }
55
56 static int get_name(const char *path, const unsigned char *sha1, int flag, void *cb_data)
57 {
58         int might_be_tag = !prefixcmp(path, "refs/tags/");
59         struct commit *commit;
60         struct object *object;
61         unsigned char peeled[20];
62         int is_tag, prio;
63
64         if (!all && !might_be_tag)
65                 return 0;
66
67         if (!peel_ref(path, peeled) && !is_null_sha1(peeled)) {
68                 commit = lookup_commit_reference_gently(peeled, 1);
69                 if (!commit)
70                         return 0;
71                 is_tag = !!hashcmp(sha1, commit->object.sha1);
72         } else {
73                 commit = lookup_commit_reference_gently(sha1, 1);
74                 object = parse_object(sha1);
75                 if (!commit || !object)
76                         return 0;
77                 is_tag = object->type == OBJ_TAG;
78         }
79
80         /* If --all, then any refs are used.
81          * If --tags, then any tags are used.
82          * Otherwise only annotated tags are used.
83          */
84         if (might_be_tag) {
85                 if (is_tag)
86                         prio = 2;
87                 else
88                         prio = 1;
89
90                 if (pattern && fnmatch(pattern, path + 10, 0))
91                         prio = 0;
92         }
93         else
94                 prio = 0;
95
96         if (!all) {
97                 if (!prio)
98                         return 0;
99                 if (!tags && prio < 2)
100                         return 0;
101         }
102         add_to_known_names(all ? path + 5 : path + 10, commit, prio, sha1);
103         return 0;
104 }
105
106 struct possible_tag {
107         struct commit_name *name;
108         int depth;
109         int found_order;
110         unsigned flag_within;
111 };
112
113 static int compare_pt(const void *a_, const void *b_)
114 {
115         struct possible_tag *a = (struct possible_tag *)a_;
116         struct possible_tag *b = (struct possible_tag *)b_;
117         if (a->depth != b->depth)
118                 return a->depth - b->depth;
119         if (a->found_order != b->found_order)
120                 return a->found_order - b->found_order;
121         return 0;
122 }
123
124 static unsigned long finish_depth_computation(
125         struct commit_list **list,
126         struct possible_tag *best)
127 {
128         unsigned long seen_commits = 0;
129         while (*list) {
130                 struct commit *c = pop_commit(list);
131                 struct commit_list *parents = c->parents;
132                 seen_commits++;
133                 if (c->object.flags & best->flag_within) {
134                         struct commit_list *a = *list;
135                         while (a) {
136                                 struct commit *i = a->item;
137                                 if (!(i->object.flags & best->flag_within))
138                                         break;
139                                 a = a->next;
140                         }
141                         if (!a)
142                                 break;
143                 } else
144                         best->depth++;
145                 while (parents) {
146                         struct commit *p = parents->item;
147                         parse_commit(p);
148                         if (!(p->object.flags & SEEN))
149                                 insert_by_date(p, list);
150                         p->object.flags |= c->object.flags;
151                         parents = parents->next;
152                 }
153         }
154         return seen_commits;
155 }
156
157 static void display_name(struct commit_name *n)
158 {
159         if (n->prio == 2 && !n->tag) {
160                 n->tag = lookup_tag(n->sha1);
161                 if (!n->tag || parse_tag(n->tag) || !n->tag->tag)
162                         die("annotated tag %s not available", n->path);
163                 if (strcmp(n->tag->tag, all ? n->path + 5 : n->path))
164                         warning("tag '%s' is really '%s' here", n->tag->tag, n->path);
165         }
166
167         if (n->tag)
168                 printf("%s", n->tag->tag);
169         else
170                 printf("%s", n->path);
171 }
172
173 static void show_suffix(int depth, const unsigned char *sha1)
174 {
175         printf("-%d-g%s", depth, find_unique_abbrev(sha1, abbrev));
176 }
177
178 static void describe(const char *arg, int last_one)
179 {
180         unsigned char sha1[20];
181         struct commit *cmit, *gave_up_on = NULL;
182         struct commit_list *list;
183         static int initialized = 0;
184         struct commit_name *n;
185         struct possible_tag all_matches[MAX_TAGS];
186         unsigned int match_cnt = 0, annotated_cnt = 0, cur_match;
187         unsigned long seen_commits = 0;
188
189         if (get_sha1(arg, sha1))
190                 die("Not a valid object name %s", arg);
191         cmit = lookup_commit_reference(sha1);
192         if (!cmit)
193                 die("%s is not a valid '%s' object", arg, commit_type);
194
195         if (!initialized) {
196                 initialized = 1;
197                 for_each_ref(get_name, NULL);
198         }
199
200         if (!found_names && !always)
201                 die("cannot describe '%s'", sha1_to_hex(sha1));
202
203         n = cmit->util;
204         if (n) {
205                 /*
206                  * Exact match to an existing ref.
207                  */
208                 display_name(n);
209                 if (longformat)
210                         show_suffix(0, n->tag ? n->tag->tagged->sha1 : sha1);
211                 printf("\n");
212                 return;
213         }
214
215         if (!max_candidates)
216                 die("no tag exactly matches '%s'", sha1_to_hex(cmit->object.sha1));
217         if (debug)
218                 fprintf(stderr, "searching to describe %s\n", arg);
219
220         list = NULL;
221         cmit->object.flags = SEEN;
222         commit_list_insert(cmit, &list);
223         while (list) {
224                 struct commit *c = pop_commit(&list);
225                 struct commit_list *parents = c->parents;
226                 seen_commits++;
227                 n = c->util;
228                 if (n) {
229                         if (match_cnt < max_candidates) {
230                                 struct possible_tag *t = &all_matches[match_cnt++];
231                                 t->name = n;
232                                 t->depth = seen_commits - 1;
233                                 t->flag_within = 1u << match_cnt;
234                                 t->found_order = match_cnt;
235                                 c->object.flags |= t->flag_within;
236                                 if (n->prio == 2)
237                                         annotated_cnt++;
238                         }
239                         else {
240                                 gave_up_on = c;
241                                 break;
242                         }
243                 }
244                 for (cur_match = 0; cur_match < match_cnt; cur_match++) {
245                         struct possible_tag *t = &all_matches[cur_match];
246                         if (!(c->object.flags & t->flag_within))
247                                 t->depth++;
248                 }
249                 if (annotated_cnt && !list) {
250                         if (debug)
251                                 fprintf(stderr, "finished search at %s\n",
252                                         sha1_to_hex(c->object.sha1));
253                         break;
254                 }
255                 while (parents) {
256                         struct commit *p = parents->item;
257                         parse_commit(p);
258                         if (!(p->object.flags & SEEN))
259                                 insert_by_date(p, &list);
260                         p->object.flags |= c->object.flags;
261                         parents = parents->next;
262                 }
263         }
264
265         if (!match_cnt) {
266                 const unsigned char *sha1 = cmit->object.sha1;
267                 if (always) {
268                         printf("%s\n", find_unique_abbrev(sha1, abbrev));
269                         return;
270                 }
271                 die("cannot describe '%s'", sha1_to_hex(sha1));
272         }
273
274         qsort(all_matches, match_cnt, sizeof(all_matches[0]), compare_pt);
275
276         if (gave_up_on) {
277                 insert_by_date(gave_up_on, &list);
278                 seen_commits--;
279         }
280         seen_commits += finish_depth_computation(&list, &all_matches[0]);
281         free_commit_list(list);
282
283         if (debug) {
284                 for (cur_match = 0; cur_match < match_cnt; cur_match++) {
285                         struct possible_tag *t = &all_matches[cur_match];
286                         fprintf(stderr, " %-11s %8d %s\n",
287                                 prio_names[t->name->prio],
288                                 t->depth, t->name->path);
289                 }
290                 fprintf(stderr, "traversed %lu commits\n", seen_commits);
291                 if (gave_up_on) {
292                         fprintf(stderr,
293                                 "more than %i tags found; listed %i most recent\n"
294                                 "gave up search at %s\n",
295                                 max_candidates, max_candidates,
296                                 sha1_to_hex(gave_up_on->object.sha1));
297                 }
298         }
299
300         display_name(all_matches[0].name);
301         if (abbrev)
302                 show_suffix(all_matches[0].depth, cmit->object.sha1);
303         printf("\n");
304
305         if (!last_one)
306                 clear_commit_marks(cmit, -1);
307 }
308
309 int cmd_describe(int argc, const char **argv, const char *prefix)
310 {
311         int contains = 0;
312         struct option options[] = {
313                 OPT_BOOLEAN(0, "contains",   &contains, "find the tag that comes after the commit"),
314                 OPT_BOOLEAN(0, "debug",      &debug, "debug search strategy on stderr"),
315                 OPT_BOOLEAN(0, "all",        &all, "use any ref in .git/refs"),
316                 OPT_BOOLEAN(0, "tags",       &tags, "use any tag in .git/refs/tags"),
317                 OPT_BOOLEAN(0, "long",       &longformat, "always use long format"),
318                 OPT__ABBREV(&abbrev),
319                 OPT_SET_INT(0, "exact-match", &max_candidates,
320                             "only output exact matches", 0),
321                 OPT_INTEGER(0, "candidates", &max_candidates,
322                             "consider <n> most recent tags (default: 10)"),
323                 OPT_STRING(0, "match",       &pattern, "pattern",
324                            "only consider tags matching <pattern>"),
325                 OPT_BOOLEAN(0, "always",     &always,
326                            "show abbreviated commit object as fallback"),
327                 OPT_END(),
328         };
329
330         argc = parse_options(argc, argv, prefix, options, describe_usage, 0);
331         if (max_candidates < 0)
332                 max_candidates = 0;
333         else if (max_candidates > MAX_TAGS)
334                 max_candidates = MAX_TAGS;
335
336         save_commit_buffer = 0;
337
338         if (longformat && abbrev == 0)
339                 die("--long is incompatible with --abbrev=0");
340
341         if (contains) {
342                 const char **args = xmalloc((7 + argc) * sizeof(char *));
343                 int i = 0;
344                 args[i++] = "name-rev";
345                 args[i++] = "--name-only";
346                 args[i++] = "--no-undefined";
347                 if (always)
348                         args[i++] = "--always";
349                 if (!all) {
350                         args[i++] = "--tags";
351                         if (pattern) {
352                                 char *s = xmalloc(strlen("--refs=refs/tags/") + strlen(pattern) + 1);
353                                 sprintf(s, "--refs=refs/tags/%s", pattern);
354                                 args[i++] = s;
355                         }
356                 }
357                 memcpy(args + i, argv, argc * sizeof(char *));
358                 args[i + argc] = NULL;
359                 return cmd_name_rev(i + argc, args, prefix);
360         }
361
362         if (argc == 0) {
363                 describe("HEAD", 1);
364         } else {
365                 while (argc-- > 0) {
366                         describe(*argv++, argc == 0);
367                 }
368         }
369         return 0;
370 }